Saying “market research on special diet foods” is too vague. Do you want to know:

- what is the demographics of the special diet food users
- how these groups purchase food and what goes into the decision making process
- where do they purchase their special food requirements
- what triggered them to become part of this group

The steps are

1. First know what you want to do in your market research.
2. Then figure out the target market for this research.
3. Then identify how this research will be done — qualitative vs. quantitative study
4. Start working on your questions